LineArt Preprocessor Provider (SEGS)

Lineart ControlNet extracts the outlines of an image - softer and more natural than Canny's hard edges - and uses them to hold structure while the model repaints inside. It's the community's favorite for keeping characters consistent across regenerations, precisely because it preserves the drawing without over-constraining color and shading. This node takes that and drops it into Impact Pack's detailer loop, so line structure gets preserved on each detected region as it's resampled, not on the whole image at once.

The payoff is subtle but real. When you detail a face or a figure, you want the resample to sharpen it, not redraw its silhouette. Lineart conditioning on the crop pins the outlines so the pass improves texture and detail while the shape stays put. It's the gentler cousin of the pose and depth providers - good when the thing you're protecting is the linework itself.

How it works

It's a provider, so it has no image input and produces no visible line map. It builds a SEGS_PREPROCESSOR recipe and outputs it. You wire that into the preprocessor slot of Impact Pack's Apply ControlNet (SEGS) node, together with a lineart ControlNet model and your SEGS. When the detailer runs, Impact Pack crops each region, extracts lineart from the crop, and applies your lineart ControlNet to that region's regeneration. The extraction lives inside the loop.

The input that matters

Just one, and it's a straight either/or:

• coarse (default off) - off gives you fine, detailed line extraction; on gives you bolder, sketchier strokes. Leave it off for realistic or detailed subjects where you want every contour held. Flip it on for stylized or anime-leaning work where thick, clean lines are the point and fine detail would just add noise.

Output is a single SEGS_PREPROCESSOR that feeds Apply ControlNet (SEGS).

Installing it

Comes with the Inspire Pack by Dr.Lt.Data - the same person behind ComfyUI Manager and the Impact Pack, so this is well-maintained, mainstream tooling. Via ComfyUI Manager: search ComfyUI Inspire Pack, install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/ltdrdata/ComfyUI-Inspire-Pack

then restart. Two dependencies you can't skip: ComfyUI's ControlNet Auxiliary Preprocessors provides the actual lineart extractor this wraps, and the Impact Pack provides Apply ControlNet (SEGS) and the SEGS machinery. Plus a lineart ControlNet model for your base.

Common issues

Errors as soon as it runs. Missing comfyui_controlnet_aux - the provider is a thin wrapper and needs that package underneath. Install it via Manager, restart.

Lines look wrong for my subject. That's the coarse toggle doing its job. Anime and clean-line work usually wants coarse on; photoreal and detailed subjects want it off. There's no universal right answer - it depends on what you're conditioning.

Nothing seems to change in the detail pass. Make sure you loaded a lineart ControlNet into Apply ControlNet (SEGS); the provider only supplies the preprocessor half. And note it only affects the regeneration of detected regions - it doesn't restructure the base image.

Nodes won't load after installing. Check the terminal log first. The recurring Inspire Pack problem is a version mismatch with Impact Pack - update the two together and restart.